1. Field of the Invention
The present invention relates to an apparatus and method for providing a biometric input for a portable terminal. More particularly, the present invention relates to an apparatus and method for recognizing a gesture as an input for a portable terminal.
2. Description of the Related Art
Portable terminals are becoming increasingly popular based on the additional and advanced features they provide in conjunction with their mobility. As advances continue to be made regarding features provided by the portable terminal, user interface design trends indicate that intuitive interface and simple interactions are also becoming increasingly popular. For example, in some instances a simple slide interface on a touch screen has replaced the traditional touch and press interface for unlocking a phone. As part of the development of intuitive interfaces, biometric recognition is being explored as a fast and convenient means to augment current user authentication and user interaction mechanisms. Biometric recognition or biometrics is a field of study that allows for recognition of an individual based on their biological and/or behavioral traits such as a fingerprint, a face, a hand, an iris, etc.
User interaction with a portable terminal can typically be categorized in two basic modes—user authentication and user input. User authentication has two basic purposes. The first is to validate the presence of the user and the second is to ensure that the user has the authority to use the phone. The first purpose, to validate the presence of the user, is to avoid an unintended execution of a function, such as avoiding the dialing of a number due to a random and unintended interaction of the portable terminal with its environment. This basic functionality is currently being provided by requiring the user to press two or more specific keys in order to unlock the phone. The second purpose, which is increasingly becoming more important with the diversification of the portable terminal as a lifestyle device, is ensuring device security. To discourage an unauthorized user, the user of the portable terminal is required to input a password to unlock the phone. User interaction is currently limited to key presses or a mouse pointer on a touch screen. However, on such a touch screen, there are basic limitations that arise from the small size of the device. Further, such an interface cannot be easily used in applications requiring 3-Dimensional (3D) scene navigation.
Use of a camera has been proposed for augmenting the user interface. For example, the prior art discloses a user interface in which the user swipes his/her finger across the camera and the direction of the swipe determines the response input to the device. As an example, a cursor may be moved in a direction corresponding to the swipe. The system of the prior art has two embodiments. In the first embodiment, the user must swipe his/her finger on the camera while the finger is in contact with the camera. A limitation of this implementation is that it is inconvenient for the user to locate the camera, especially if it is on the back side of the cell phone. In the second embodiment, the user can sway his/her finger in front of the camera in order to achieve the same effect. However, the system may not specifically recognize the finger, especially if there is a significant movement in the background, which may lead to a false positive.
A natural extension of this system is to recognize the user's finger using techniques available in the biometric recognition literature. That is, the prior art provides an exhaustive review of available biometric recognition techniques. However, a limitation of the biometric recognition techniques is that the sensors used to capture biometric features are specialized to the application in order to acquire high quality captures and thus are very expensive as compared to the generic components used in a portable terminal. That is, known methods of extracting biometric information from a user require using a specialized sensor. However, because the price of these special sensors is so high, their use is effectively prohibited in a portable terminal. Accordingly, there is a need for an apparatus and method that provides for biometric recognition while maintaining costs at a reasonable level. Moreover, there is a need for an apparatus and method that provides a biometric sensor using a camera of a portable terminal. Given that cameras in portable terminals are ubiquitous, incorporating the proposed biometric sensing will add value without adding complexity.